EDSAC on your desk.

From: Allison J Parent <allisonp_at_world.std.com>
Date: Tue Sep 22 22:19:03 1998

< It's not unheard of for a domestic mains supply in the UK to be 240V _at_
< 80A or even 100A. If I had a PDP10, you can be sure I'd find a way to ge
< such a supply.

In the USA (MA) 100-200A service pannels are common with both 120/240
ouputs typically under 15A for 120 loops and veriable for the 240. It's
fairly trivial to drop a 30A 240 single phase and in my garage I have a
plug for one if needed.

KL10 8KW is likely not real but a max.

< Ouch. That's about 25% efficient. Sorry, but that does need to be
< redesigned, particularly if it's a switcher.!

for that kind of efficientcy it would have to be a very poor linear
as most of them are in the 45-65% range. I'm skeptical that the input
load is really 8KW and in reality far less. I'm inclined to believe
something more in the range of 4kw is the truth.

For example I'm running 4 VS3100s and the name plate says 5.8A at 120v
on the back of the /m76 yet the /M10E it's only 1.2A... the reson is the
/m76 can daisy chan the AC power out to another box (switched) but the
internal power supply is only a 150w switcher needing 1.2A. The
underline is that 8kw may well be the AC distribution bus load not the
local processor power load.

< > However, RP06 drives are another matter entirely. They need three-pha
< > power for their motors. I'm reluctant to try the capacitor trick.

That works well if the values are right. Keep in mind that the motors
are running under a mostly static load so despite their size and power
they are running at a fraction of their full load power.
 
< There are electronic 3-phase converters sold in the UK (and I think
< Elektor published as design for one). They are typically used for small
< (2-3hp) motors on machine tools. I would guess that an RP06 would run of
< one of those without any problems.

Rotary converter, low efficentcy but they work and can be built.

Allison
Received on Tue Sep 22 1998 - 22:19:03 BST